FIGURE 3.

The N- and C-terminal regions of IbpA are not essential for interaction with IbpB. A, IbpA, IbpAΔN, or IbpAΔC was incubated in the absence or presence of His-IbpB at indicated temperatures, followed by the addition of Ni-NTA-agarose. After extensive washing, the proteins associated with the Ni-NTA-agarose were eluted with a high concentration of imidazole, subjected to SDS-PAGE, and stained with Coomassie Brilliant Blue. B, interaction between IbpAΔN and IbpB blocks the fibril formation. Representative electron micrographs of negatively stained complexes between IbpA or IbpAΔN with IbpB. IbpA or IbpAΔN (2 μm) were heat-treated in presence of IbpB (7.8 μm) at 48 °C for 10 min (upper panels). In the control experiments (lower panels), the indicated proteins were incubated separately as above. Afterward, the samples were cooled and combined together at room temperature. Nominal magnification, 15,500×.